Hammer coral not opening on 1 branch

[DeNovice]

I have a hammer coral with two branches. One head on each branch. One is fully extended and happy. The other - which receives equal light and similar flow, is only about 25% open. Up until two days ago they were both doing great. It had been there for at least 3 weeks without an issue.

I’m new to the hobby so while I can find plenty about hammers and torches not opening, I can’t seem to find something on why only one head won’t open but the other is fine. It’s possible the one may have had some contact with the rock but without a change in flow why would it decide to hole up now? If that we’re the issue how long should I expect it to not be fully opening after relocating it away from the rock? I did move it about 4 hours ago and no change.

I appreciate the advice anyone can offer. This site is a hobby saver for newbs like me.

 

[Pistondog]

Any shrimp or filefish in the tank?

 

[DeNovice]

Any shrimp or filefish in the tank?

Just a cleaner. He’s a jerk when I target feed but doesn’t mess with them otherwise. No crabs. A few small blue leg hermits but that’s it. One clown and watchman for fish. It’s only a 20 gal.

 

[DeNovice]

Bump. Still contracted today.